Tray lifter



Dec. 2, 1969 E. ROTHSCHILD 3,481,448

TRAY LIFTER Filed Dec. 22, 1967 2 Sheets-Sheet l INVENTOR. EdgarRgthschild hw/AW ATTORNEYS.

Dec. 2, 1969 E. ROTHSCHILD 3,481,448

TRAY LIFTER Filed Dec. 22. 1967 2 Sheets-Sheet 2 INVHVTOR. EdgerRothschild by (y ATTORNEYS.

United States Patent US. Cl. 198-136 2 Claims ABSTRACT OF THE DISCLOSUREThe invention relates to a three conveyor system for transporting trayshorizontally then vertically, from one floor to another for example, andthen horizontally again when the trays have reached the height desired,all without abruptly changing the direction of the trays at any pointand without stacking the trays.

This invention relates to a device for taking on, lifting or loweringand discharging of trays, particularly trays of the type used incafeterias and restaurants connected with institutions such as hospitalswhere said trays are loaded with food-stuff in one area and then must bedelivered to another higher or lower area.

In restaurants connected with hospitals and similar institutions, thefood is prepared in the kitchen which is at one level, is loaded ontotrays of a size which is suitable for one patient and then must bedelivered to another floor or level before being given to the patient orother customer. Mechanical devices for lifting such trays from one floorto another have been developed but such devices, based mostly on theprinciple of the dumbwaiter, require that the tray or trays be deliveredthereto in one direction, horizontally for example, then the directionof motion of the tray and its contents is sharply changed to a verticaldirection, and finally after the vertical motion comes to a halt thetray is removed in another horizontal direction. Thus in being deliveredfrom one level to another the tray and its contents (part of thecontents usually being liquids), is stopped and started several times.Attempts to speed up the feeding of such trays to and removal of suchtrays from the lifting device necessarily results in spilling andsplashing of the liquid contents of the trays. Also the feeding of traysto such a lifting device must be intermittent since a second tray cannotbe fed onto the lifting mechanism until the previous tray has beenlifted up to completely clear the oncoming tray.

Among the objects of the present invention is to provide a device whichsubstantially continuously takes on a series of trays, feeds themupwardly or downwardly and thence horizontally at the desired level, allwithout any sudden changes in direction.

The objects of the invention are attained by connecting a horizontalconveyor means with a lifting or lowering device of the type having apair of spiral tracks winding about a vertical axis, and connecting thelatter with a second horizontal conveyor at the desired discharge point.Means are provided to automatically force the tray from thespiral tracksonto the discharge conveyor and such means can be attached at variouspoints with respect to the spiral tracks to vary the discharge area asdesired.

The trays are pushed along the spiral tracks by a series of rods held ona rotating spider and suspended from above or projected upwardly frombelow so that said rods can pass between the tracks at all levels whenthe spider is rotated.

In the accompanying drawing which illustrates, by way of example, aconstructional form of the invention:

FIG. 1 is an elevational view, partly in section of the device of theinvention.

Patented Dec. 2, 1969 FIG. 2 is a top view of the device of FIG. 1.

The device as a whole comprises one or more horizontal loading conveyors10, the spiral conveyor with a vertical axis 20 and one or moreunloading conveyors 50, 51. The loading and unloading conveyors aresuitably belt type conveyors. The loading conveyor 10, for example,comprises an endless belt 11, held between two rollers 12 and 13, thelatter roller being rotatably mounted within the cage formed in thespiral conveyor 20 between the drum 21 and series of vertical supports22 thereof.

The spiral conveyor 20 comprises the drum 21 fixed upon the top surface23 of the frame structure 24, 25. The drum 21 is suitably reinforcedfrom the inside by caps 26 and 29 and rings 27 and 28. Attached to theouter surface of the drum 21 by welding for example, are a series ofbrackets 31-1 to 3113, etc., which are so arranged that a helical spiraltrack 32 of uniform pitch may be supported thereby. Extending downthrough the drum 21 is the shaft 33 which is rotatably mounted inbearings 34 and 35 positioned adjacent the central openings in caps 26and 29. The lower end of shaft 33 is connected mechanically by means 36,illustrated diagrammatically, by which said conveyor 10 is driven fromsaid shaft 33. Suitable means including the bevel gears 37, 38 areprovided to positively rotate the shaft 33.

Attached to the upper portion of shaft 33 is the spider 39 containingthe plurality of arms (in this case six) 41, 41-1, 41-2, 41-3, 41-4 and41-5 on the ends of which the rods 42, 4 2-1, 42-2, 42-3, 42-4 and 425are attached. On rotation of the spider 39, the rods 42 to 42-5 movearound the drum 21 in the space outside of track 32 and inside of track43 (to be described below).

Secured to the rim of the top surface 23 of the support 24, 25 are aplurality of uprights 22-1, 22-2, etc., forming the cage 22. Theuprights 22-1, 22-2, etc. are further reinforced by means of reinforcingrings 41-1, 44-2, 44-3 and 44-4. Secured to the uprights 22-1, 22-2,etc., are a plurality of brackets 45-1 to 45-13 on which the spiraltrack 43 is mounted to parallel the track 32.

The tracks 32 and 43 can be formed of any material which preferably hasa low coefficient of friction. Suitable materials are plastics such aspolyethylene, polypropylene, Teflon, polyvinyl chloride, polycarbonates,nylon, etc. Although shown as being flat in shape the tracks can in factbe made with the cross sectional shape of a T or an I or may haveplurality of reinforcing ribs on the under or upper sides thereof.Ordinarily, trays containing a single meal are not very heavy and arugged track is not necessary. If desired, tracks formed of a series ofrollers such as used in roller conveyors may be employed. The pusherrods 42 to 425 are preferably positioned just slightly outside of theimaginary cylindrical surface which bisects the space between the twotracks 32 and 43 so that any tendency that the pusher rods have to turnthe trays away from the exact spiral path, tends to turn such traystoward the central drum 21 so that, in effect, the trays are guided bythe tracks 32 and 43 and occasionally by the surface of drum 21.

The trays can be discharged at almost any desired point between twoadjacent uprights 22-1 to 22-11 in the area adjacent the spiral tracksby afiixing the discharge angle piece 60 to the drum 21 in the path ofthe tray at the region where the discharge is desired. Said angle piece60 comprises a pair of cars 61, 62 which pass through predeterminedholes in the drum 21 and are clamped on the inside of the drum. Thesloping surface 63 of said angle piece 60 is adapted to contact the edgeof the tray and as the tray is squeezed between the rod 42 and thesurface 63 it is guided between the two uprights 22-2 and 22-7 of FIG.2, for example, where it is picked up by conveyor belt 50 andtransported horizontally.

The features and principles underlying the invention Q described abovein connection with specific exemplifications will suggest to thoseskilled in the art many other modifications thereof. It is accordinglydesired that the appended claims shall not be limited to any specificfeature or details thereof.

I claim:

1. An apparatus for transporting a series of loaded trays in acontinuous manner, first in a horizontal direction thence vertically andfinally horizontally without abruptly changing the direction thereofcomprising a horizontal belt conveyor, spiral conveyor means to take thetrays from the belt conveyor and transport them vertically in a spiralpath and a second horizontal belt conveyor for taking said trays fromsaid vertical conveyor,

said spiral conveyor means comprising a cylindrical drum adapted tosupport the first of a pair of spiral tracks in a position spaced fromthe outer surface thereof,

a cage structure arranged concentric to and outside of said cylindricaldrum, means extending from said cage structure to support the second ofsaid pair of spiral tracks in a position extending inwardly from saidcage toward said drum and parallel to put spaced from said first track,

spider means supported to rotate on a vertical axis which isconcentrically with respect to said drum, said spider means includingspider arms extending above the space between said pair of tracks,

a plurality of pusher rods one afiixed to each of said spider armsextending substantially the full length of the space between said trackswhereby rotation of said spider means causes at least one of said rodsto push a tray positioned on said track so that said tray moves on saidspiral tracks,

discharge means having a sloping surface which projects into the path ofa tray travelling on said spiral path, said discharge means beingpositioned opposite the second horizonal belt conveyor whereby a traypushed into contact with said discharge means passes onto said secondbelt conveyor.

2. The device as claimed in claim 1 wherein said pusher rods areadjusted to extend just outside of the imaginary cylindrical surfacebisecting the space between the pair of spiral tracks.

References Cited UNITED STATES PATENTS 1,085,852 2/1914 Duncan l98--2121,177,502 3/1916 Ewald 198-212 EVON C. BLUNK, Primary Examiner ROGER S.GAITHER, Assistant Examiner US Cl. X.R.

